1. Field of the Invention.
The present invention relates generally to a method and apparatus for lining a tubular member, such as a steel pipe, with a synthetic liner, the liner being securely bonded within the pipe interior without the application of heat, vacuum or chemical bonding agents.
2. Description of the Prior Art.
Fluid-carrying pipes are often subject to corrosion and other conditions which are detrimental to the life of the pipe, or to the fluids moving through the pipe. Plastic inserts have been used in the past for protective purposes but generally involve cumbersome and difficult procedures for effectively installing such liners, and particularly in sealing them to the wall of pipe.
U.S. Pat. No. 3,494,813, to Lawrence et al, Feb. 10, 1970, shows a method for installing a plastic liner in a pipe by using vacuum to draw the liner into the pipe and to assure tight sealing engagement between the liner and the pipe wall.
U.S. Pat. No. 1,708,141, to Kepler, Apr. 9, 1929, shows a method of lining a pipe with an elastomeric lining in which the lining is pushed through a reducing die and coated with cement.
U.S. Pat. No. 3,462,825, to Pope et al, Aug. 26, 1969, shows a method for lining a tubular member with a fluorocarbon liner having an initial outside diameter greater than the inside diameter of the tubular member. The liner is placed in the tubular member by gripping one end of the liner and pulling it through a reducing die and into the tubular member. The liner is then released, allowing it to expand into engagement with the inner wall of the tubular member. Although certain of the above methods have attempted to install synthetic liners within tubular conduit without the use of heat, adhesives or vacuum, these methods have generally failed to effect a linear elongation of the synthetic liner so that the liner maintains a standard dimensional ratio and returns to a predetermined size to fill out and conform to the internal diameter of the surrounding pipe.
An object of the present invention is to provide an improved synthetic liner for a tubular member in which the liner is firmly held in position within the tubular member by reason of radial pressure exerted on the tubular member by the synthetic liner.
Another object of the invention is to provide a method for installing a liner within a tubular member which places the liner in a condition of circumferential compression to provide a firm bond with the surrounding tubular member.
Another object of the invention is the provision of a liner for a tubular member which is installed without the necessity of heating the liner with the risk of imparting thermal stresses to the liner.
Another object of the invention is to provide a method for lining a tubular member without the use of chemical bonding agents which, on occasion, fail to provide uniform bonding of the liner to the surrounding tubular member.